Nanofluids including metal or metal-oxide nanoparticles have shown improved thermal performance compared to water. Introducing zinc into a water-containing component of the primary system of a boiling water reactor or pressurized water reactor nuclear power plant is known to prevent the deposition of radioactive cobalt and to reduce the possible susceptibility of component materials to corrosion. Also, it is well known that silicon carbide (SiC) is a promising material for advanced reactors. Therefore, preparations of zinc oxide (ZnO) and SiC nanofluids have been used in diverse methods to reduce inconsistency of nanofluid performance. Thermal-fluid characterizations were carried out under the control of the preparation methods. In addition, indirect checks by contact angle measurements of depositions have shown that ZnO and SiC nanofluids as a self-recovering/healing coating solution can contribute to advanced nuclear safety systems in terms of the critical heat flux margin. The results show that more efforts are needed to develop the nanofluid formulation to tailor the desired properties.